You are over thinking it...the outlet port to circulate/drain the molten metal would be the same hole the lower plasma injector uses. By using a curved surface

You are over thinking it...the outlet port to circulate/drain the molten metal would be the same hole the lower plasma injector uses. By using a curved surface it can take advantage of the centrifugal force and surface tension of the liquid metal to prevent the metal from falling down lower into the injector. So basically there is a doughnut shaped orifice around the top of the lower plasma injector that's connected to a pipe which feeds into the liquid metal circulation system. Here is a cutaway drawing where you can see it: http://1.bp.blogspot.com/_VyTCyizqrHs/ScF7J2w-TOI/AAAAAAAADL8/1J2ryeF54Q8/s1600/gf0.jpg http://1.bp.blogspot.com/_VyTCyizqrHs/ScF7J2w-TOI/AAAAAAAADL...